I have posted this here also: Parked at Loopia 823
I'm writing this for a custom application that uses attachment_fu but I thought it might interest some people here who are have problems with rmagick or image_science.
rmagick is causing large memory spikes for my application and my host will not install image_science, I tried out image_science locally and the thumbnails it produces are too blurred anyway.
So if you are interested in mini_magick for attachment_fu head over to the beast forums and check out my inept attempt at creating a processor.